Printed Chalcogenide/Metal Heterostructured Photodetectors for Flexible Near‐Infrared Sensing

Abstract Near‐infrared (NIR) photodetectors can be fabricated for various applications, such as imaging, military tracking, and medical diagnosis. However, achieving miniaturization and high responsivity for NIR photodetector arrays is still a challenge. In this study, a high‐density NIR photodetector array with a micro/nano chalcogenide and silver nanoparticle heterostructure is achieved using a low‐cost printing strategy. The Ag/Ge 2 Sb 2 Te 5 (GST)/Ag heterostructure is fabricated using a template‐assisted sequential printing strategy. At an absorption wavelength of λ = 980 nm, the NIR photodetector has a high light responsivity of 6.7 × 10 4 A W −1 owing to the high crystallinity of the GST microwire and refined GST/Ag heterointerface during the printing process. In addition, the sensing pixel interval can be reduced to 25 µm, corresponding to the highest resolution of NIR photodetectors achieved thus far (resolution: 1.0 × 10 3 dpi). In addition, the NIR photodetector printed on soft substrates exhibits flexibility. Thus, a simple and effective strategy for the fabrication of NIR photodetectors is demonstrated, and precise flexible infrared sensing is achieved.